Molded carbonaceous materials are used as deodorants, decoloring agents, adsorbents, catalyst carriers, conductive electrodes, and polarized electrodes in electric double layer capacitors, among others.
So far known molded carbonaceous materials are as follows:
One example is the one produced by mixing a carbonaceous powder, such as active carbon, graphite, or carbon black, with glass frit, molding the mixture, heating the same to thereby melt the glass frit and cooling the same for solidification.
Another example is the one produced by mixing a carbonaceous powder such as mentioned above with tar, pitch, a binder and a solvent, and molding the mixture.
A further example is the one obtained by mixing active carbon with a binder such as polyvinyl alcohol or polyvinylpyrrolidone.
As for the first and second types of carbonaceous materials, however, the so-called carbonating activation by blowing high temperature steam against the materials is required for providing them with surface activity, since each carbonaceous powder particle 1 is surrounded by glass, tar, pitch and/or the like 2, as shown in FIG. 1.
Carbonaceous materials of the third type are particularly useful as polarized electrodes of electric double layer capacitors. However, they occur as pastes and therefore work is required for the filling of cells with them in the process of cell manufacture. Accordingly, solid polarizable electrodes are rather desirable from the viewpoint of easy handling. For actual use as polarized electrodes, the above mentioned pastes are impregnated with an electrolytic solution such as sulfuric acid.